1. Field of the Invention
This invention relates to duct hangers, and it more particularly relates to an easy to manufacture and install expandable duct hanger.
2. Description of the Prior Art
Most buildings, whether residential or commercial construction, contain ducts as part of their heating, ventilating and cooling systems. These ducts are generally suspended from the floor joists. Installation of these ducts becomes complex in situations where the distance between the joists is not uniform. In U.S. Pat. No. 3,163,386, an adjustable duct hanger is disclosed which is manually adjustable to fit the distance between a pair of adjacent floor joists. This duct hanger has prongs welded onto either end which are pounded into the floor joists. One problem with this prior art is that the welded prongs tend to break due to fracturing of the weld. Another problem is that the duct hanger is complicated to manufacture, particularly in an efficient and practical manner. A further problem is that adjusting this duct hanger to the desired size during installation is difficult because the high area of surface contact between the sliding parts results in friction which impairs the ease of movement between the sliding parts. The present invention solves these problems in a unique manner.
It is an object of the present invention to provide an easy to manufacture expandable duct hanger.
Another object of the present invention is to provide an expandable duct hanger which is sturdy and durable.
Another object of the present invention is to provide an expandable duct hanger such that the duct hanger is inexpensive to manufacture, and easy and economical to produce.
Still another object of the present invention is to provide an expandable duct hanger whose parts slide easily when connected, making adjustment of the duct hanger simple.
Still another object of the present invention is to provide an expandable duct hanger which is strong and will not break during installation.
Other objects will be apparent from the description to follow and from the appended claims.
The foregoing objects are achieved according to a preferred embodiment of the invention by means of a two piece expandable duct hanger having one piece with a ridge which slides into a channel in the other piece, each piece also having a prong on one end to secure and hold the duct hanger into the floor joists.